Abdominal muscles, together with the back muscles, provide support for the trunk of a human body and enable its movement in different directions. These muscles are layered, and especially the muscles closer to the spine, the so-called inner abdominal muscles (the transverse abdominal muscle and the internal oblique muscles), affect the posture and stability of the trunk as well as the appropriate placement of internal organs.
Well-trained inner abdominal muscles are known for promoting trunk control and thus back health. However, they are also important in almost any type of physical activity, ranging from ballet dancing to racket sports, such as tennis. In addition to their strength, also the ability to control and be aware of the muscles is essential for sports performance. Focused force production during specified stages of movement determines how the power produced by the body is conveyed to the actual object to be moved by that power. Inner abdominal muscle control also adds to the balance of the movement, thus helping the athlete to rapidly proceed to the next movement. Further, improved inner abdominal muscle control can help rehabilitate patients and elderly whose muscle strength has declined for some reason. Improved trunk control can prevent them from falling or developing body misalignments that could lead to further injuries or functional disorders.
In the patent document WO 2013038129, an exercise device is disclosed comprising an elongated handle and, at the distal end of the handle, at least one roller. The roller is configured to be in contact with the surface along which the exercise device is arranged to move. The axis of the portion of the handle supporting the roller is offset to the axis of the part of the handle which is held by the user.
There are also other types of training devices targeted to exercise abdominal muscles. However, typical for all the solutions is that they focus on the heaviness of the exercise motion due to some sort of a resistance to the movement. Since the muscles are required to work throughout the exercise motion, these solutions do not train the user to focus on the timing and control of the inner abdominal muscle activity, but center on the increase of muscle strength.